1. Technical Field
Example embodiments of the present invention relate in general to a device-to-device (D2D) communication method and more specifically to channel state measurement, data transmission/reception, and power control methods necessary to perform D2D communication in a cellular-based wireless mobile communication system.
2. Related Art
D2D communication is a communication scheme in which direct data transmission/reception is performed between two devices adjacent to each other without passing through a base station. That is, two devices, one of which serves as a data source and a data destination respectively, communicate with each other.
Various discussions may be made on use cases in which D2D communication may be efficiently used. For example, D2D communication may be used in a local media server that provides a large amount of data (for example, programs of a rock concert and information on a musician) to audience at a rock concert and the like.
At this time, while devices connected to a serving cell may perform telephone communication, Internet access, or the like using an existing cellular link, they directly transmit and receive the above-mentioned large amount of data from the local media server operating as a communication partner device of D2D communication according to a D2D scheme. On the other hand, a D2D link may be established between devices within different serving cells as well as between devices within the same serving cell.
A cellular network-based D2D communication scheme in the above-described D2D communication is a scheme in which a device desiring to communicate with another device requests a central node (a base station in a cellular network), which performs control, to establish a link, and the central node enables the device to perform D2D communication with a communication partner device by assigning radio resources for the D2D communication when the communication partner device is located around the device.
At this time, the overall operation of the device is managed by the central node, and radio resources assigned to a cellular link or another D2D link for the D2D communication may be reused.
Many advantages and disadvantages coexist in the communication of the existing cellular scheme of the related art and the above-described D2D communication. Accordingly, a communication system in which mobile communication of the cellular scheme is combined with the above-described D2D communication is ultimately expected to be widespread.
However, many technical parts such as adaptive transmission, scheduling, and power control of D2D communication necessary for performing the above-described D2D communication are not supported in the current cellular network.